Informe El medio ambiente en Europa: Estado y perspectivas 2020

PART 2
TABLE 5.3 Soil organic carbon by land use category in the period 2009-2015
Land use category Number of samples Mean SOC (g/kg)
2009 2015
Permanent grassland 2 230 42.0 43.8
Long-term cultivated land 5 018 17.9 17.3
Rice 5 22.8 19.2
Permanent crops 704 15.6 16.4
Natural vegetation 4 167 91.7 90.4
Wetlands 23 432.6 456.5
Source: Hiederer (2018).
through fertiliser, manure, biosolids
and nitrogen‐fixing crops exceed critical
values beyond which eutrophication
can be expected (e.g. critical ammonia,
or NH 3
, emissions to remain below
critical loads, or 2.5 mg N/l in run-off to
surface waters) (Map 5.5). On average
across Europe, about a 40 % reduction
in nitrogen inputs would be needed to
prevent this exceedance (De Vries et al.,
forthcoming). Map 5.5 (left) presents
the nitrogen surplus, being the
difference between nitrogen inputs and
uptake by plants, which is a measure of
the potential pollution of air and water
(De Vries et al., forthcoming).
Biological degradation and the
decline in soil organic matter
Soils deliver key ecosystem services
such as nutrient provision, water
purification, filtering of pollutants
and a habitat for soil organisms.
Non‐degraded soils provide these
functions simultaneously and to a level
needed for ecosystem performance
(Chapter 3). Two closely connected
indicators are the basis of soil
multifunctionality, the soil organic
carbon (SOC) pool and soil biodiversity.
Carbon is one of the primary sources of
energy in food webs; losses of carbon
The increased intensity
of land use has negatively
affected the species richness
of earthworms, springtails
and mites across Europe.
(through erosion, climate change,
drainage of otherwise waterlogged
soils) impact the supply of ecosystem
services and reduce biodiversity (Stolte
et al., 2016). Biologically mediated
decomposition of organic material is
the fundamental process for building
the soil carbon stock, which, together
with clay minerals, are important for
nutrient retention and cycling.
Different forms of soil degradation
(SOC loss, tillage, pollution, compaction
and erosion) negatively impact the
habitat available for soil organisms. In
all regions across Europe, the species
richness of earthworms, springtails
and mites has been negatively affected
by increased intensity of land use
(Tsiafouli et al., 2015). Healthy soils
contain active microbial (bacteria and
fungi) and animal (micro to macro
fauna) communities (Orgiazzi et al.,
2016), of which bacteria and fungi are
mainly responsible for nutrient cycling,
which is essential for plant growth.
The dynamics of SOC vary according
to land use and specific management
practices. Forest soils currently act as
a strong sink for carbon (30-50 % of
the current sink by forest biomass)
(Luyssaert et al., 2010). In a recent
assessment covering 2009-2015, carbon
in mineral cropland soils in the EU-28
was shown to be broadly stable or
slightly declining (albeit at much lower
levels compared with other land cover
categories) (Table 5.3), while carbon
in grasslands showed slight increases
(Hiederer, 2018); similar results were
also reported from national soil
monitoring (e.g. Kobza, 2015; Kaczynski
et al., 2017). It should be noted that
the LUCAS sampling programme has
only recently started, so the currently
available 6-year interval is relatively
short to demonstrate significant
changes in SOC stocks.
The largest amounts of SOC are found
in organic soils such as peat (Byrne and
et al., 2004; spatial extend of peat and
mires, see Tanneberger et al., 2017).
Cultivation of organic soils causes large
carbon dioxide (CO 2
) emissions. Such
carbon losses contribute significantly to
the negative greenhouse gas balance
SOER 2020/Land and soil
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